Conventionally various methods have been proposed to recover aluminium from materials containing metallic aluminium, but they have demerits in that the recovery rate of aluminium is low, it is difficult to separate the accompanying impurities (or unnecessary materials) such as paint, organic materials (paper, resin and the like) and iron, and therefore the metallic aluminium content in the reclaimed aluminium is low.
The known techniques for recovering aluminium are, for example, as follows.
(1) Method for manufacturing flake powder or twist unshaped small granular articles of metallic aluminium (see Patent Publication No. 52-19180). PA1 (2) Method for recovering plastics and aluminium from the wrapper waste of medical tablets (see Patent Kokai No. 52-112673). PA1 (3) Method for removing organic coatings from scrap aluminium (see Patent Publication No. 59-37337). PA1 (4) Method for recovering aluminium from waste aluminium cans and subjecting it to a pre-treatment for reclaiming and melting it (see Patent Publication No. 2-53494). PA1 (5) The method of recovering Al-foil from band shape Al-laminate scrap, comprises 1) heating the Al-laminate in non-oxidised atoms. at 400-600 deg. C. to carbonize paper and plastics; 2) subjecting the carbonized substances to crushing to pulverise the carbonized materials, followed by separation of Al-foil from the carbonized materials (see Patent Kokai No. 60-230942). PA1 (1) The first step of crushing and/or shearing the materials containing metallic aluminium PA1 (2) The second step of separating metallic aluminium from the crushed articles
Each of the above-mentioned known techniques involves a great number of complicated steps, and the recent wastes which contain or accompany metallic aluminium have various components, so that such techniques are very costly in equipment to recover metallic aluminium in a simple way, and evidently they have difficulty in their workability.